Sequential coupler for radio frequency circuits or the like



Dec. 3, 1957 R. A. DAVIS 2,815,442-

SEQUENTIAL COUPLER FOR RADIO FREQUENCY CIRCUITS OR THE LIKE Filed June23 1955 l R055 A. DAVIS INVEVTOR. BY

HIS ATTORNEY United tates Patent SEQUENTIAL COUPLER FOR RADIO FREQUENCYCIRCUITS OR THE LIKE Ross A. Davis, Los Angeles, Calif.

Application June 23, 1955, Serial No. 517,459

6 Claims. (Cl. 250-20) This invention is related to improvements in R.F.coupling of R.-F. circuitry, for example, the coupling and circuitrywhich assure simple and effective sequential coupling of R.-F.circuitry, for example, the coupling of dual antennas to a singlereceiver.

In earlier patent applications, such as Serial Nos. 487,535 and 503,190,filed in behalf of the present inventor on February 11, 1955 and April22, 1955, respectively, there are described several embodiments ofantenna systems, for use particularly with vehicles, which rely upon thederivation of a pair of signals from discontinuities in the metalstructure. Such antenna systems are completely inconspicuous and aremuch less subject to man-made and natural types of interference than arethe conventional whip or other types of antennas. In application SerialNo. 503,190, there is shown a sequential coupling device in which therotor plates effect the coupling between input and output platesassociated with a pair of signal sources. Certain experiments have shownthat under some conditions the desired degree of decoupling may not bereached when the rotor plates are absent from proximity to the relatedstator plates in the foregoing application, and in the art known toapplicant. Because what is ultimately desired is a switching phenomenonby which the signals from the separate sources are alternately switchedto the translating circutis, a large change in the coupling between thecondition of the presence of the rotor plates and their absence isessential.

Therefore, it is an object of this invention to provide a rotarysequential coupling device for a plurality of R.-F. circuits whichexhibits a large change in the coupling between input and outputelements as the rotor revolves.

It is a further object of this invention to provide an antenna inputsystem for dual antennas which insures the maximum rejection of theundesired signal when the selector is in the position for coupling ofthe desired signal to the associated receiving apparatus.

According to one form of the present invention the stator of theselector is made up of two groups each group including two sets ofplates lying in spaced parallel planes with the vanes in each set lyingsubstantially opposite the vanes in its associated set, the vanes havingsubstantially the shape of a sector of a circle, and a rotor havingplates also shaped as a sector of a circle of sectorial angle not lessthan that of the stator plates is rotated between the spaced sets ofstator plates. The disposition of the rotor plates is such that when thesets of plates in one group of stators are coupled the other sets ofplates in the other group are shielded from each other by interposedrotor plates, the rotor being grounded. The output signals from thesequential selector are then injected into a dual or single multi-gridinput stage of the radio receiver.

The features of the present invention which are believed to be novel areset forth with particularity in the appended claims. The presentinvention, both as to its or gauization and manner of operation,together with further 2,815,442 Patented Dec. 3, 1957 ICC objects andadvantages thereof, may best be understood by reference to the followingdescription, taken in connection with the accompanying drawing, inwhich:

The sole figure is a schematic representation of one embodiment of thisinvention.

In the sole figure antenna 10 may be of the type described in thecopending application, Serial No. 503,190, filed by the presentapplicant, which antenna may be described generally as a closed loopformed by the conductive boundary about a discontinuity in the structureor vehicle. Output wire 11 from antenna 10 is connected to antennatuning circuit 12 the output of which is con nected through connector 13to stator plate 14 which is in the first set of stator plates 15, theother plate in that set being plate 16 which is electrically connectedto plate 14. A second antenna 17, which provides a signal spacephasedwith respect to the signal from antenna 10, has its output signalcoupled through connector 18 to antenna tuning circuit 19, the output ofwhich is connected through conductor 20 to stator plate 21 in the secondset of stator plates 22, the other member of which being stator plate 23which is electrically joined to stator plate 21. Set 15 and set 22 areelectrically insulated from each other and may lie in the same plane.Stator plate 24 and stator plate 25 in set 26 are coupled throughconnector 27 to input grid 28 of vacuum tube 29, the anode 30 of whichis coupled to amplifier tank circuit 31 and to anode 32 of vacuum tube33. Stator plates 34 and 35 of set 36 are joined electrically and areconnected to grid 37 of vacuum tube 33 through conductor 38. It is to benoted that sets 15 and 26 form a first group and sets 22 and 36 form asecond group of stator plates. All of the stator plates havesubstantially the same shape, name ly that of a sector of a circle, andhave substantially the same sectorial angle. The plates in set 26 aredisposed opposite to the plates in set 15 and lie in substantiallyparallel planes, each set being insulated electrically from the other.correspondingly, the plates in set 36 are disposed substantiallyopposite the plates in set 22, lie in substantially parallel planes andare insulated from each other. Rotor 43 includes interconnected plates39, 40, 41 and 42 all of which lie in a plane parallel to the planes ofthe stator plates, the rotor being spaced and insulated from the statorplates. The rotor is connected through an appropriate contact to groundpotential.

The operation of the foregoing circuit is as follows. Signals derivedfrom antenna 10 after preselection in circuit 12 are applied to plates14 and 16 in set 15. Signals derived from antenna 17, after apreselection in circuit 19, are applied to plates 21 and 23 in set 22.With rotor 43 in the position shown in the sole figure there is anunobstructed path for lines of force flowing from the stator plates inset 22 to the stator plates in set 36, whereas rotor plates 39 and 40shield the plates in set 15 from the plates in set 26. Hence, sets 22and 36 are intercoupled and radio frequency signals from antenna 17 maypass to input grid 37 and ultimately appear amplified in output circuit31. When rotor 43 rotates one sector angle, the contrary conditionexists, namely plates 14 and 16 are coupled to plates 24 and 25,respectively, and plates 21 and 23 are shielded by plates 41 and 42 fromstator plates 34 and 35. Hence, radio frequency signals from antenna 10pass to grid 28 of vacuum tube 29 and appear at the output circuit 31.This sequence continues as rotor 43 revolves. By driving rotor 43 at anespecially high speed and selecting the proper number of plates and theproper segment angle no interference is apparent in the output from thesystem which may be attributed to the technique utilized. If some lossin performance can be tolerated, conductor 38 may be connected directlyto grid 28 and vacuum tube 33 may be eliminated. This would also permitthe merging of sets 36 and 26 into a solid disc. The disadvantages ofsuch an arrangement are that they provide a generally undesiredadditional capacitance directly from grid 28 to ground potential.

From the foregoing discussion it is apparent that there has beenprovided a sequential dual antenna system which is particularlyadaptable to radio installations in vehicles, propulsion forces forrotation of rotor 43 being available from the electrical, pneumatic,mechanical or hydraulic systems of the vehicle itself. Such sequentialselection by its elimination of dual channel circuitry greatly reducesthe cost of dual antenna systems of this type. It should be understoodthat, although this discussion has been directed to dual antennas, anynumber of antennas or other signal sources may be coupled to a commonload, such as a receiver, through this selector by simple changes invane size, number and distribution. Multiple mixing tubes, or singletubes with multiple mixing grids may be utilized in such systems.

While particular embodiments of the present invention have been shownand described, it will be obvious to those skilled in the art thatchanges and modifications may be made without departing from thisinvention in its broader aspects, and, therefore, the aim in theappended claims is to cover all such changes and modifications as fallwithin the true spirit and scope of this invention.

I claim:

1. A coupling element for sequential intercoupling of a plurality ofradio-frequency circuits including first, second, third and fourth setsof stator plates, each plate in each such set being of a shapeapproximating a sector of a circle, the sectorial angle of each suchplate having a predetermined value, such sets being disposed in firstand second groups each group including at least two sets of plates lyingin spaced substantially parallel planes and electrically insulated fromeach other, and a rotor including a plurality of plates each havingsubstantially the shape of a sector of a circle, the sectorial angle ofwhich approximates that of said stator plates, and the disposition ofwhich is such as to alternately shield the sets within each group fromeach other as said rotor rotates, said rotor being adapted forconnection to ground potential.

2. Apparatus according to claim 1 in which said sectorial angle of saidrotor and stator plates approximates 45.

3. Apparatus according to claim 1 in which said sectorial angle of saidstator plates is not less than the sectorial angle of said rotor plates.

4. Apparatus according to claim 1 in which said rotor plates aresymmetrically disposed about an axis and are interconnectedelectrically.

5. Apparatus according to claim 1 in which said first and second sets ofstator plates make up said first group and said third and fourth sets ofstator plates make up said second group, means for applying signals froma first antenna to said first set and for extracting signals from saidsecond set when said rotor plates are disposed between said third andfourth sets, and means for applying signals from a second antenna tosaid third set and extracting signals from said fourth set when saidrotor plates are disposed between said first and second sets.

6. An antenna system for a vehicle radio receiver including: means forderiving a pair of space-phased signals from at least one discontinuityin the vehicle body; a sequential coupling element including first,second, third and fourth sets of stator plates, each plate in each suchset being of a shape approximating a sector of a circle, the sectorialangle of each such plate having a predetermined value, said first andsecond sets of stator plates making up a first group of plates and lyingin spaced substantially parallel planes and electrically insulated fromeach other, said third and fourth sets of stator plates making up asecond group of plates lying in spaced substantially parallel planes andelectrically insulated from each other, and a rotor including aplurality of plates each having substantially the shape of a sector of acircle, the sectorial angle of which approximates that of said statorplates, and the disposition of which is such as to alternately shieldthe sets within each group from each other as said rotor rotates, saidrotor being adapted for connection to ground potential; and means forapplying the first of said pair of signals to said first set of statorplates and the second of said pair of signals to said third set ofstator plates, and for extracting the signals which appear sequentiallyat said second and fourth sets of stator plates as a result of theoperation of said rotor.

References Cited in the file of this patent UNITED STATES PATENTS1,600,842 Philips Sept. 21, 1926 1,917,290 Beverage et al. July 11, 19332,309,068 Hermansson Jan. 19, 1943 2,461,832 Meacham Feb. 15, 19492,587,156 Havenhill et al. Feb. 26, 1952 2,703,866 De la Cova et a1 Mar.8, 1955

